Aqueous chromatography system using pH- and temperature-responsive stationary phase with ion-exchange groups

Area of Science:

• Analytical Chemistry
• Polymer Science
• Chromatography

Background:

• Developing advanced stationary phases is crucial for efficient chromatographic separations.
• Responsive materials offer tunable properties for selective analyte interactions.
• Nonsteroidal anti-inflammatory drugs (NSAIDs) require robust analytical methods for quality control.

Purpose of the Study:

• To develop a novel pH- and temperature-responsive hydrogel for HPLC stationary phases.
• To evaluate its efficacy in separating NSAIDs like ibuprofen, ketoprofen, and naproxen.
• To explore its potential for ion-exchange and temperature-responsive chromatography.

Main Methods:

• Synthesized a copolymer of N-isopropylacrylamide (NIPAAm), butyl methacrylate (BMA), and N,N-dimethylaminopropylacrylamide (DMAPAAm).
• Modified aminopropyl silica beads with the cross-linked copolymer (IBD hydrogel).
• Evaluated the IBD hydrogel as an HPLC packing material using an isocratic aqueous mobile phase.

Main Results:

• The stationary phase exhibited tunable surface properties (hydrophilic/hydrophobic, charged/non-charged) with changes in temperature and pH.
• Temperature changes influenced the accessibility of ion-exchange groups on the polymer surface.
• NSAID interactions were effectively controlled by manipulating temperature and pH.

Conclusions:

• The developed pH- and temperature-responsive hydrogel is a promising HPLC stationary phase.
• This chromatography technique offers precise control over analyte interactions.
• It is expected to be valuable for separating pharmaceuticals and biomolecules.